Reverse nested blank stacker

ABSTRACT

A stacker for converting two separate streams of blanks into two separate stacks and for delivering the stacks to a delivery unit comprises a lower stack-forming magazine to which one stream is conveyed and an upper stack-forming magazine to which the other stream is conveyed. A primary elevator located below the lower magazine has a surface for receiving the stack formed by the lower magazine. A secondary elevator located below the upper magazine has a selectively operable conveyor surface for receiving the stack formed by the upper magazine. The primary and secondary elevators are movable between upper and lower positions with the surfaces of the primary and secondary elevators being in the same plane when both elevators are in lower position. A plunger is provided for moving a stack sideways from the surface of the primary elevator to the conveyor surface of the secondary elevator when both elevators are in lower position, i.e., when both stacks are formed. Means, such as a photo electric cell, are responsive to movement of a stack from the primary elevator onto the secondary elevator for initiating operation of the conveyor surface of the secondary elevator to move both stacks onto the delivery unit adjacent the discharge end of the stacker.

United States Patent 1 Zernov et a1.

[ 1 Nov. 6, 1973 REVERSE NESTED BLANK STACKER [75] Inventors: Peter Zernov; Thomas H. Gabel,

both of Wauwatosa, Wis.

[73] Assignee: Zerand Corporation, New Berlin,

Wis.

[22] Filed: Sept. 29, 1972 [21] Appl. No.: 293,344

[52] U.S. C1. 214/6 H, 53/155, 93/93 DP, 214/65, 53/162 [51] Int. Cl. 865g 57/16 [58] Field of Search 214/6 P, 6.5, 6 H6 DK; 53/155, 162; 93/93 DP; 271/88 [56] References Cited UNITED STATES PATENTS 3,379,320 4/1968 Loach et al 214/65 3,488,693 l/l970 Brinkmeier 214/6.5

Primary Examiner-Robert .l. Spar Attorney-James E. Nilles [57] ABSTRACT A stacker for converting two separate streams of blanks into two separate stacks and for delivering the stacks to a delivery unit comprises a lower stack-forming magazine to which one stream is conveyed and an upper stack-forming magazine to which the other stream is conveyed. A primary elevator located below the lower magazine has a surface for receiving the stack formed by the lower magazine. A secondary elevator located below the upper magazine has a selectively operable conveyor surface for receiving the stack formed by the upper magazine. The primary and secondary elevators are movable between upper and lower positions with the surfaces of the primary and secondary elevators being in the same plane when both elevators are in lower position. A plunger is provided for moving a stack sideways from the surface of the primary elevator to the conveyor surface of the secondary elevator when both elevators are in lower position, i.e., when both stacks are formed. Means, such as a photo electric cell, are responsive to movement of a stack from the primary elevator onto the secondary elevator for initiating operation of the conveyor surface of the secondary elevator to move both stacks onto the delivery unit adjacent the discharge end of the stacker.

9 Claims, 6 Drawing Figures PATENIEBNUY 6 ms SHEET u 0F 6 m mi 323mm imEt Nb S 35 :mucouom PATENIED NOV s 1973 SHEET 5 OF 6 START Brake Bar42 Down Elevators 71 and 72 Up FIG.6

Valve 140 for Secondary Elev t Valve 141 for Primary Elevator Sec. ElUp NO LS6 YES E Sec.El.72 Conveyor Belts 77 Stop Brake Bar 42 Up Sec. El. 72 Conveyor Belts 77 On l Brake NO Bar Up YES 42 On High Conveyor Belts 41 and Speed Timer Valve 140 for SeoElevator 72 OFF Valve 141 f Conveyor Belts Pri Elevator 41and 42 on Bra. 71 OFF Slow Speed Bar Brake Bar Down Solenoid Valve 142 PATENIEDnuv 6 1915 3770.142

SHEET 8 OF 6 v Y (Concinued) 2w [Plunger 102 Extend 1 YES SecEL72 DeLiveryUnit I2 Plgr Conveyor Belts Conveyor BeLtslZl plunfer 102 Retc START START Re \L S7 YES YES

Motor for Del. Unit Belts 121 START Delivery Unit Delivery Unit Receiving Primary 12 Lift Belts 121 Table Elevator 71 RAISE STOP START UP i NO R Stacker f NO OFF W-(man YES ON Delivery Unit Belts12l Secondary &Receiving Table Elevator 7 STOP Delivery Unit 12 Lift LOWER S -Elevator E Belts 7? p NO NO YES REVERSE NESTED BLANK STACKER BACKGROUND OF THE INVENTION This invention relates generally to stacker machines for stacking blanks cut from a web and being delivered in shingled streams. In particular, it relates to a stacker wherein two streams of blanks (of different types or orientations) are delivered to two separate magazines which simultaneously form two separate stacks containing the same number of blanks.

DESCRIPTION OF THE PRIOR ART The prior art discloses stackers wherein specified numbers of identically shaped, similarly orientated carton blanks cut from a continuous web of material are delivered in shingled relationship to a magazine which forms the blanks into stacks on an elevator. The elevator gradually descends as the blanks accumulate and each finished stack is automatically moved by a plunger from the elevator onto a receiving unit such as a table or conveyor at the discharge end of the stacker.

In some instances it is desirable that blanks of the same shape be cut from the web in such a manner that each blank has a reverse orientation from the blank adjacent to it. Heretofore, it was necessary to separate the blanks according to their orientation and then direct them to separate stackers wherein they were then stacked so that each stack contained blanks of the same orientation. This procedure required separate costly stackers and axuiliary equipment and doubled the amount of floor space required for installation.

SUMMARY OF THE PRESENT INVENTION The present invention contemplates web cutting and stripper apparatus which delivers a continuous stream of blanks, each in reverse orientation from an adjacent blank, which need to be separated according to orientation and then stacked. In accordance with the present invention there is provided a reverse nested carton blank stacker which includes deflector means for directing blanks of one orientation onto a primary (lower) stripper delivery table (conveyor) and for directing blanks of the other orientation onto a secondary (upper) stripper delivery table (conveyor). EAch stripper delivery table is provided with separate plows to prealign the stream of blanks thereon and delivers its blanks past brake-bar means which operate intermittently to divide the blanks into groups of predetermined numbers. The primary and secondary delivery conveyors feed their streams to a primary (lower) slowspeed conveyor and to a secondary (upper) slow-speed conveyor, respectively. Each slow-speed conveyor feeds its stream of blanks to a magazine (for stacking purposes) and past a jogger associated therewith. Each of the slow-speed conveyors is provided with driven wheels which ride on top of the blanks to enhance the positive movement of the blanks on the conveyors. The primary and secondary magazines are located above vertically movable primary and secondary elevators, respectively, which support the stacks being formed by the magazines. The vertical position of each elevator is individually controlled by a hydraulic sensing unit to maintain a constant blank entry angle and also to gradually lower the completed stacks to a position for discharge onto a delivery unit, such as a table or conveyor, at the discharge end of the stacker. The primary elevator comprises a flat stationary surface on which its stack is supported. The secondary elevator comprises a laterally movable conveyor. In lowered position the surfaces of the primary and secondary elevators are in the same plane. Plunger means are located adjacent the primary elevator and operate to push the completed stack on the primary elevator onto the conveyor on the secondary elevator when both elevators are in lowered position. Means, such as a photo electric cell, responsive to movement of the stack onto the secondary elevator, initiates operation of the conveyor on the secondary elevator to transfer both stacks to the delivery unit.

DRAWINGS FIG. I is a side elevational view of apparatus in accordance with the invention, including a portion of a cutter-stripper machine, a reverse nested blank stacker, and a delivery unit;

FIG. 2 is a top plan view of a portion of a web from which blanks are cut and stripped for stacking by the stacker shown in FIG. 1;

FIG. 3 is an isometric view of the delivery unit and of the discharge end of the stacker with stacks of blanks on the delivery unit;

FIG. 4 is an enlarged side elevational view of the two elevators and related components of the stacker shown in FIG. 1;

FIG. 5 is a schematic diagram of the hydraulic control system for the apparatus shown in FIG. 1; and

FIG. 6 is a diagram showing the sequence of operation of components in the apparatus in FIG. 1 during a typical cycle of automatic operation.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 is a side elevational view of apparatus in accordance with the invention, including a portion of a cutter-stripper machine 10, a reverse nested blank stacker 11, and a delivery unit 12. Cutter-stripper machine 10 is adapted to cut and strip blanks, such as blanks A, B, A and B, from a continuous web 13 shown in FIG. 2 and to supply them to stacker 11 wherein they are arranged into stacks and supplied to delivery unit 12 for transport to another location for packing into shipping containers.

As FIG. 2 shows, the blanks A, B, A and B cut from web 13 are all of the same size and configuration. However, the blanks A and B are cut from one side of web 13 and the blanks A and B are cut from the other side and each blank A is reversely orientated from each blank B, as is each blank A from each blank B. Therefore, cutter-stripper machine 10 supplies two separate parallel streams of blanks to the input end of stacker 1 l and the adjacent blanks in each stream are reversely disposed from each other. It is to be understood that stacker 11 is adapted to receive the two parallel streams of blanks from cutter-stripper l0 and to process both streams simultaneously in accordance with the invention. However, for purposes of simplification in the following description, only operations pertaining to the stream initially containing reversely disposed blanks A and B will be discussed, except where otherwise noted.

As FIG. 1 shows, stacker 11 comprises a standard motor-driven alternator unit 14 at its input end which receives the the alternately disposed blanks A and B from cutter-stripper 10 and diverts or separates them into a primary (lower) stream containing blanks A and referred to herein as stream AA,and a secondary (upper) stream containing blanks B and referred to herein as stream BB.

Stacker 11 also comprises a primary (lower) stripper delivery table or conveyor 15 and a secondary (upper) stripper delivery table or conveyor 16 located directly above table 15 onto which the streams of blanks AA and BB, respectively, are directed by alternator unit 14. The delivery tables 15 and 16 comprise flexible conveyor belts 17 and 18, forward end rolls 19 and 20 and rear end rolls 21 and 22 about which the belts are arranged, and guide roll assemblies 23 and 24, respectively. The forward end rolls 19 and 20 are motordriven adjustable speed rolls and move the upper surfaces of the belts 17 and 18, respectively, and the streams AA and BB thereon in the direction of the arrows 25 in FIG. I. The delivery tables 15 and 16 are provided with vibrating plows 31 and 32, respectively, which pre-align the streams of blanks thereon. Tables 15 and 16 are also provided with drive wheels 33 and 34, respectively, which ride on top of the blanks and enhance positive movement thereof. The blanks in the streams AA and BB are in shingled or overlapped relationship and those in stream AA are reversely disposed with respect to those in stream BB. The tables 15 and 16, the plows 31 and 32, and the drive wheels 33 and 34 may be of the type disclosed in US. Pat. application Ser. No. 094,481, filed by Zernov et al for Carton Blank Aligning Apparatus and assigned to the same assignee as the present application.

Stacker 1! further comprises a primary (lower) slowspeed conveyor 35 and a secondary (upper) slow-speed conveyor 36 located directly above conveyor 35. Secondary conveyor 36 is vertically movable for adjustment purposes by a pair of hydraulic cylinders 37 shown in FIGS. 4 and 5. Secondary conveyor 36 extends beyond the discharge end of primary conveyor 35 for clearance purposes. The conveyors 35 and 36 comprise flexible conveyor belts 41 and 42, forward end rolls 43 and 44, and rear end rolls 45 and 46, respectively. The forward end rolls 43 and 44 are motordriven adjustable speed rolls and move the upper surfaces of the belts 41 and 42, respectively, and the blanks thereon in the direction of arrows 25 in H6. 1. During certain portions of the stacking cycle the delivery tables 15 and 16 and the conveyors 35 and 36 all operate at the same adjustable speed and that speed is automatically variable to suit the input speed of the blanks from cutter-stripper to maintain the blanks in shingled and constantly spaced relationship. However, during other parts of the stacking cycle, the speed of the conveyors 35 and 36 with respect to the speed of the tables and 16, respectively, increases for a short time interval. The conveyors 35 and 36 are provided with drive wheels 47 and 48, respectively, which ride on top of the blanks and enhance positive movement thereof.

A brake bar means generally designated 42 is disposed between table 15 and primary conveyor 35 and between table 16 and secondary conveyor 36. The brake bar means 42 functions to automatically provide a gap or space in the movement of the files or streams of blanks being conveyed in shingled relationship along the tables 15 and 16. The brake bar means 42 comprise a lower member 51 and an upper member 52, each of which is positioned transversely to the direction of travel of the streams AA and 1313, respectively. The

members 51 and 52 are vertically movable upwardly at predetermined intervals to engage the blanks and momentarily stop or hold the blanks while the speed of the conveyors 35 and 36 is increased to provide gaps in the two streams AA and BB. The gaps are of sufiicient length to allow for removal of the blanks being stacked in stacker 11. The members 51 and 52 are simultaneously movable vertically by means of a hydraulic cylinder 54, shown in FIGS. 4 and 5.

A primary (lower) stack-forming magazine 61 and a secondary (upper) stack-forming magazine 62 are located at the discharge ends of the lower and upper conveyors 35 and 36, respectively. The magazines 61 and 62 define spaces within machine 11 wherein vertical stacking of the streams of blanks being delivered thereto takes place. The magazines 61 and 62 are associated with jogging paddle assemblies 63 and 64, respectively. Each jogging paddle assembly functions to align the blanks being formed into a stack by its associated magazine. US. patent application Ser. No. l 1 1,564 filed by Abler and Zernov for Jogger Assembly for Carton Blank Stacker and assigned to the same assignee as the present application, discloses a jogger assembly adaptable for use in the present invention.

The primary magazine 61 and secondary magazine 62 are located directly above vertically movable primary and secondary elevators 71 and 72, respectively. The elevators 71 and 72 are adapted to receive and support the stacks being formed by the magazines 61 and 62, respectively. The elevators 71 and 72 are vertically movable by hydraulic cylinders 73 and 74, respectively, between fully raised and fully lowered positions, as F168. 4 and 5 show. The height of each elevator is continuously changed as the height of the stack thereon increases so that the top of the stack is positioned just below its magazine. The vertical position of each elevator is individually controlled by sensing means, hereinafter described, to maintain a constant blank entry angle and also to gradually lower a completed stack to a position for discharge onto a receiving unit 12. Primary elevator 71 comprises a flat surface 75 and secondary elevator 72 comprises a flat surface 76 which takes the form of the upper side of conveyor belts 77 which are laterally movable in the direction of the arrows 25. When the elevators 71 and 72 are in fully lowered position, as shown in H6. 1, the surface 75 is slightly above surface 76 and surface '76 is slightly above the top of the rollers 78 of delivery unit 12.

As FIG. 4 shows, cylinder 73 for primary elevator 71 is rigidly secured in vertical position to a portion of the framework 80 of stacker 11 and its vertically movable piston rod 81 is attached to spaced apart members 82, shown in H6. 3, which define the flat surface 75. Cylinder 74 for secondary elevator 72 is also rigidly secured in vertical position to a portion of the framework 80 of stacker 11 and its vertically movable piston rod 82 carries a rotatable pinion gear 83 which is in constant mesh with a first rack 84 rigidly secured to a side of framework 80 and is also in constant mesh with a second rack 85 rigidly secured to secondary elevator 72. Vertical movement of piston rod 82 effects rotation of pinion gear 83 and corresponding vertical movement of secondary elevator 72. Secondary elevator 72 also comprises spaced apart rolls 87 around which the belts 77 are disposed. One of the rolls 87 is a selectively operable motor-driven roll which effects movement of belts 77. Rigid stationary fiat members 89 bridge the gap between the elevators 71 and 72 when both are lowered to enable sliding transfer of stacks of blanks therebetween.

Stacker 11 further comprises plunger means, generally designated 100, and including a push plate 101 and a hydraulic cylinder 102. Plunger 100 is disposed adjacent elevator 71 and operates to push a completed stack on the primary elevator 71 laterally onto the secondary elevator 72 when both elevators are in lowered position.

Means including a photo electric cell sensing unit 110 are provided above member 89 and are responsive to movement of a stack from elevator 71 onto elevator 72 to initiate operation of the conveyor belts 77 on secondary elevator 72 to transfer both stacks to delivery unit 12 onto the idler rolls 78 thereof.

Delivery unit 12 takes the form of a conveyor which is disposed at the discharge end of stacker 11 and is adapted to move stacks placed thereon at right angles to the path of movement of the streams of blanks in stacker 11. Unit 12 comprises two rolls 120, one of which is a motor-driven roll, around which a plurality of belts 121 are arranged. The upper surfaces of the belts are movable in the direction of arrow 122. An idler roll 78 is located between each pair of belts 121 and each idler roll is disposed transversely to the rolls 120. The belts 121 and the two rolls 120 form an assembly which is vertically movable. Control means are provided which, when the last stack has cleared secondary elevator 72, cause the rolls 120 to stop rotating and also causes the rolls 120 and the belts 121 to be raised and to commence moving so as to move the stacks clear of the idler rolls 78 and to transport the stacks to some point of discharge. The lift assembly comprising rolls 120 and belts 121 is vertically movable by a hydraulic cylinder 123, as FIGS. 1 and 5 show.

FIG. 5 shows schematically the electro-hydraulic control circuit for operating the hydraulic cylinders hereinbefore referred to. The circuit comprises hydraulic fluid supply means including a fluid reservoir 130, a pump 131 driven by an electric motor 132, a main fluid supply line 133, and a needle valve 134 and pressure gauge 135 for monitoring fluid pressure in supply line 133. Main supply line 133 is connected to and supplies fluid to branch lines 136, 137 and 138. Branch line 136 supplies brake bar cylinder 54, plunger cylinder 102 and the secondary conveyor lift cylinders 37. Branch line 137 supplies primary elevator cylinder 73. Branch line 138 supplies the secondary elevator cylinders 74 and delivery unit lift cylinder 123. Fluid flow from the branch lines to the individual cylinders is regulated or controlled by either manually or electrically operated control valves. The three valves designated by the numerals 140, 141 and 142 are understood to be three-position (raise, lower, neutral) solenoid operated valves. The two valves designated by the numerals 143 and 144 are three-position (raised, lower neutral) manually operated four-way rotary valves. The two valves designated by the numerals 145 and 146 are twoposition (open, close) solenoid operated valves. The three valves designated by the numerals 147, 148 and 149 are two-position (raise, lower) solenoid operated valves. Three flow control devices designated 150, 151 and 152 are provided and located as follows. Device 150 is located on the extend side of the brake bar cylinder 54 to control its raise operation. Devices 151 and 152 are located on the retract and extract sides, respectively, of plunger cylinder 102 to control its movement in both directions.

A solenoid operated plunger by-pass valve 148A and a flow control device 14813 are located in the hydraulic circuit between valve 148 and flow control device 151 to initially slow down the movement of the piston of cylinder 102 when plunger is initially operated to push a completed stack laterally. This is to prevent the stack from being struck too rapidly or forcefully and to prevent it from being upset. The solenoid of by-pass valve 148A operates in response to a signal from an electric timer means 148C, shown in FIG. 5, which effects operation of valve 148A to slow down plunger 100 until it hits the stak, at which point the timer 148C concludes its timing cycle and causes the solenoid to shift the spool of by-pass valve 148A so as to contact plunger 100 for subsequent operation at its norman speed of movement.

The solenoid operated valves shown in FIG. 5 and other drive components for the apparatus operate in response to actuation of cam-operated limit switches which are shown in FIGS. 1 and 4 and designated LS1 through LS9 and in response to photo sensing unit 110. The limit switches and sensing unit control the sequential operation of the various machine components during a switching cycle and provide correct timing. The cams for operating the limit switches are adjustable to suit particular conditions. Switch LS1 is a magazine adjust switch. Switch LS2 is a stack height control switch which is adjustable to control the height of a stack and is used when the batch count switch unit 44 on cutterstripper 10 is not being relied on. Switch LS3 is a primary elevator-up switch which operates to stop the primary elevator 71 in its uppermost position. Switch LS4 is a primary elevator-down switch which operates to stop the primary elevator 71 in its lowermost position. Switch LS5 is a secondary elevator-down switch which operates to stop the secondary elevator 72 in its lowermost position. Switch LS6 is a secondary elevator-up switch which operates to stop secondary elevator 72 in its uppermost position. Switch LS7 is a plunger retract switch which effects raising of the primary elevator 71 when plunger plate 101 is fully retracted. Switch LS8 is a plunger extend switch which immediately effects retraction of the plunger plate 101 after it has been fully extended. Switch LS9 is a brake bar-up switch which controls the height to which the brake bar means 42 can be raised.

To prevent accidental triggering of photo sensing unit 110, as by a stray blank falling through the light beam thereof, a latching relay (not shown) is provided to prevent the signal from photo sensing unit from effecting its normal function until the plunger retract limit switch LS7 is actuated by forward motion of plunger 1011. In other words, the sensing unit 110 is functionally operative only during the period that plunger 100 is in extended position, i.e., that period commencing from the time when plunger 100 operates limit switch LS7 by moving away from it during forward motion and until it again returns and depresses limit switch LS7.

Operation of the limit switches LS1 through LS9 and photo sensing unit 110 is explained in the following description of operation.

OPERATION As FIGS. 1 through 6 make clear, apparatus in accordance with the invention operates as follows. Assume that cutter-stripper 10 is in operation and is providing two parallel streams of blanks to alternator 14 of stacker 11. One stream contains alternately arranged blanks A and B and the other contains alternately arranged blanks A and B. Also assume that main switch 56 of stacker 11, in FIG. 6, is ON and that all motors and control circuits for the stacker are energized for operation in the automatic mode or sequence so that the stacker will provide four stacks of blanks, orientated as shown in FIG. 3, of a predetermined height or number during each cycle of operation. With main switch 56 ON, pump motor 132 is energized and the motors for the tables 15 and 16 and the conveyors 35 and 36 are in operation at the same speed. Further assume that the elevators 71 and 72 are in full up position, that brake bar means 42 is down, and that the belts 121 of delivery unit 12 are stationary and in down position.

The automatic stacking cycle can be initiated to effect stacking according to either the number of blanks in a stack or the height ofa stack. In the count mode, the cycle starts when the counter switch or unit 44 on cutter-stripper l0 completes a count signal. In the height" mode, the cycle starts when the stack reaches a certain height and effects cam operation of stack height limit switch LS2. Both switches 44 and LS2 are adjustable to vary the count or height as desired within machine limits.

Once the automatic cycle is initiated, the sequence is as follows. Brake-bar means 42 moves upwardly into clamping or blocking position in response to extend operation of brake-bar cylinder 54 and interrupts the streams of blanks AA and BB between the tables 15 and 16 and the conveyors 35 and 36, respectively. Timing of brake-bar means 42 is controlled by a time delay relay "FD-3, in FIG. 6 which, for example, maintains it in up (blocking) position for one and a half seconds and in down position for one second. When brake-bar means 42 is up, the conveyors 35 and 36 begin to operate at high speed instead of at their normal slow speed. The time interval of conveyor high speed operation is adjustable and is controlled by time delay relay TD-2. Both the primary and secondary elevators 71 and 72, respectively, begin to descend as the blanks on the conveyors 35 and 36,, respectively, are formed into stacks thereon by the magazines 61 and 62, respectively. When the stacks on the elevators 71 and 72 are completely formed, time delay relay TD-2 causes the conveyors 35 and 36 to slow down from high speed to normal or low speed. When this occurs, brake-bar means 42 descends to again permit blank streams AA and BB to feed onto the conveyors 35 and 36 from the tables 15 and 16, respectively. When both elevators 71 and 72 reach their lowermost position, their descent stops due to the action of the limit switches LS4 and LS5, respectively, and both elevator surfaces 75 and 76 come to rest in lower position. Timing of elevator operation is such, for example, that primary elevator 71 is up for one second and down for one and a half seconds while secondary elevator 72, which has a longer vertical travel, is up for two and a half seconds and down for two and a half seconds. At this time, the plunger means 100 begins to extend laterally and its plate 101 engages the side of the stack (or stacks) formed on primary elevator 71 to slide the stack into secondary elevator 72..

When the beam of photo electric cell unit 110 is broken by the leading edge of the stack being moved by plate 101, a signal is provided which initiates operation of the conveyor belts 76 on secondary conveyor 72 and also starts the timer TD-4. The conveyor belts 76 on secondary conveyor 72 move the stack (or stacks) initially formed thereon and the stack (or stacks) pushed thereonto to the delivery unit 12. More specifically, the stacks are moved onto rolls 78 of delivery unit 12, as shown in FIG. 3. As this movement of the stacks is occurring, the plunger means retract. Tirnewise, for example, plunger means 102 require 3 seconds to extend and 2 seconds to retract. Simultaneously with the retraction of the plunger 100, the elevators 71 and 72 begin to rise toward their normal uppermost position in preparation for the next stacking cycle. Extension and retraction of the plunger 100 is controlled by operation of the limit switches LS7 and LS8.

The stacks transferred to delivery unit 12 are initially arranged as shown in FIG. 3 and rest on the upper surfaces of the walls 78. Timer TD-4 hereinbefore referred to, after allowing time for the stacks to be positioned and come to rest on delivery unit 12, initiates raising of the rolls and the belts 121 thereon so that these belts engage the stack bottoms and raise the stacks clear of (above) the rolls 78. A predetermined time interval after this has occurred, time delay relay TD-6 starts the belts 121 to move the stacks in the direction of arrow 122 shown in FIG. 3. When the stacks are moved clear of delivery unit 12, a time delay relay TD-S causes the belts 121 both to stop and to lower below the level of the surfaces of the rolls 78. In a typical cycle, for example, the belts 121 are raised for about eight seconds and are lowered for about 10 seconds. Meanwhile, the elevators 71 and 72 have returned to and come to rest in their uppermost positions in readiness for the next stacking cycle as a result of the operation of the appropriate limit switches.

It is to be understood that apparatus in accordance with the invention can process blanks of a shape other than that shown and that one or more parallel streams of blanks from cutter-stripper unit 19 could be simultaneously processed. Furthermore, the physical location and arrangement of the limit switches could be other than that shown, provided they functioned to provide sequential operation of system components in accordance with the invention.

RESUME The present invention contemplates web cutting and stripper apparatus 10 which delivers a continuous stream of blanks such as blanks A and B, each in reverse orientation from an adjacent blank, which need to be separated according to orientation and then stacked. In accordance with the present invention there is provided a reverse nested carton blank stacker 11 which includes deflector means 14 for directing a stream of blanks AA of one orientation onto a primary (lower) stripper delivery table (conveyor) 15 and for directing a stream of blanks BB of the other orientation onto a secondary (upper) stripper delivery table (conveyor) 16. The stripper delivery tables 15 and 16 are provided with separator plows 31 and 32, respectively, to prealign the streams of blanks thereon and deliver them past brake-bar means 42 which operate intermittently to divide the blanks into groups of predetermined numbers. The primary and secondary delivery conveyors 15 and 16 feed their streams to a primary (lower) slow-speed conveyor 35 and to a secondary (upper) slow-speed conveyor 36, respectively. Each slow-speed conveyors 35 and 36 feeds its stream of blanks to magazines 61 and 62, respectively, (for stacking purposes) and past joggers 63 and 64, respectively, associated therewith. The slow-speed conveyors 35 and 36 are provided with driven wheels 47 and 48, respectively, which ride on top of the blanks to enhance the positive movement of the blanks on the conveyors. The primary and secondary magazines 61 and 62 are located above vertically movable primary and secondary elevators 71 and 72, respectively, which support the stacks being formed by the magazines. The vertical position of each elevators 71 and 72 is individually controlled by a hydraulic sensing unit to maintain a constant blank entry angle and also to gradually lower the completed stacks to a position for discharge onto a delivery unit 12, such as a table or conveyor, at the discharge end of stacker 11. The primary elevator 71 comprises a flat stationary surface 75 on which its stacks is supported. The secondary elevator 72 comprises laterally movable conveyor belts 77 defining a surface 76. In lowered position the surfaces 75 and 76 of the primary and secondary elevators 71 and 72, respectively, are almost in the same plane. Plunger means 100 are located adjacent the primary elevator 71 and operate to push the completed stack on the primary elevator 71 onto the conveyor belts 77 on the secondary elevator 72 when both elevators are in lowered position. Means, such as a photo electric cell 110, responsive to movement of the stack onto the secondary elevator 72, initiates operation of the conveyor belts 77 on the secondary elevator 72 to transfer both stacks to the delivery unit 12. Delivery unit 12 comprises rolls 78 onto which the stacks are delivered. Delivery unit 12 also comprises conveyor belts 121 on rolls 120 which can be raised between the rolls 78 to engage the stack bottoms to move the stacks away from the stacker.

We claim:

1. In a stacker for converting two separate streams of blanks into two separate stacks and for delivering said stacks to a delivery unit;

a first stack-forming magazine to which one stream is conveyed,

a second stack-forming magazine to which the other stream is conveyed,

a primary elevator located at the discharge end of said first magazine and having a surface for receiving the stack formed by said first magazine,

a secondary elevator located at the discharge end of said second magazine and having a selectively operable conveyor surface for receiving the stack formed by said second magazine,

said primary and secondary elevators being movable between upper and lower positions with the surface of the primary elevator being above that of the secondary elevator when both elevators are in lower position,

a plunger for moving a stack from the surface of the primary elevator to the conveyor surface of the secondary elevator when both elevators are in lower position,

and means responsive to movement of a stack from the primary elevator onto the second elevator for initiating operation of the conveyor surface of said secondary elevator to move both stacks onto said delivery unit.

ill

2. A stacker according to claim 1 wherein said first magazine is at a lower level than said second magazine.

3. A stacker according to claim 2 wherein said first and second elevators are located below said first and second magazines, respectively.

4. A stacker according to claim 3 including: lower and upper conveyors for delivering said streams of blanks to said first and second magazines, respectively; primary and secondary delivery conveyors for delivering said streams of blanks to said lower and upper conveyors, respectively; and brake means for periodically interrupting the streams of blanks between said primary delivery conveyor and said lower conveyor and between said secondary delivery conveyor and said upper conveyor to control the number of blanks in said stacks.

5. A stacker according to claim 4 wherein said delivery unit is a conveyor located at the discharge end of said stacker.

6. A stacker according to claim 5 including deflector means at the input ends of said primary and secondary delivery conveyors for receiving a single stream of blanks and for dividing said single stream into said separate streams.

7. Apparatus for converting a single stream of reversely orientated blanks into two separate stacks and for delivering said stacks to a delivery unit comprising:

primary and secondary delivery conveyors;

deflector means at the input ends of said primary and secondary delivery conveyors for receiving said single stream of blanks and for diverting blanks of one orientation onto said primary delivery conveyor and blanks of the other orientation onto said secondary delivery conveyor;

lower and upper slow-speed conveyors for receiving streams of shingled blanks from said primary and secondary delivery conveyors, respectively;

brake means for periodically interrupting the stream between the primary delivery conveyor and the lower slow-speed conveyor and between the secondary delivery conveyor and the upper slowspeed conveyor to control the number of blanks being processed by said slow-speed conveyors;

a first stack-forming magazine at the discharge end of said lower slow-speed conveyor;

a second stack-forming magazine at the discharge end of said upper slow-speed conveyor, said second magazine being at a higher elevation than said first magazine;

a primary elevator located below said first magazine and having a surface for receiving the stack formed by said first magazine;

a secondary elevator located below said second magazine and having a selectively operable laterally movable conveyor surface for receiving the stack formed by said second magazine;

said primary and secondary elevators being movable between upper and lower positions with the surface of the primary elevator being above that of the secondary elevator when both elevators are in lower position;

a plunger for moving a stack laterally from the surface of the primary elevator to the conveyor surface of the secondary elevator when both elevators are in lower position;

and means responsive to movement of a stack from the primary elevator onto the secondary elevator 1 l 12 for initiating operation of the conveyor surface of 9. Apparatus according to claim 8 wherein the consaid secondary elevator to move both stacks laterveyor of said delivery unit moves stacks thereon laterally onto said delivery unit. ally with respect to the paths of stream movement in 8. Apparatus according to claim 7 wherein said delivthe apparatus. ery unit comprises a conveyor. 

1. In a stacker for converting two separate streams of blanks into two separate stacks and for delivering said stacks to a delivery unit; a first stack-forming magazine to which one stream is conveyed, a second stack-forming magazine to which the other stream is conveyed, a primary elevator located at the discharge end of said first magazine and having a surface for receiving the stack formed by said first magazine, a secondary elevator located at the dischargE end of said second magazine and having a selectively operable conveyor surface for receiving the stack formed by said second magazine, said primary and secondary elevators being movable between upper and lower positions with the surface of the primary elevator being above that of the secondary elevator when both elevators are in lower position, a plunger for moving a stack from the surface of the primary elevator to the conveyor surface of the secondary elevator when both elevators are in lower position, and means responsive to movement of a stack from the primary elevator onto the second elevator for initiating operation of the conveyor surface of said secondary elevator to move both stacks onto said delivery unit.
 2. A stacker according to claim 1 wherein said first magazine is at a lower level than said second magazine.
 3. A stacker according to claim 2 wherein said first and second elevators are located below said first and second magazines, respectively.
 4. A stacker according to claim 3 including: lower and upper conveyors for delivering said streams of blanks to said first and second magazines, respectively; primary and secondary delivery conveyors for delivering said streams of blanks to said lower and upper conveyors, respectively; and brake means for periodically interrupting the streams of blanks between said primary delivery conveyor and said lower conveyor and between said secondary delivery conveyor and said upper conveyor to control the number of blanks in said stacks.
 5. A stacker according to claim 4 wherein said delivery unit is a conveyor located at the discharge end of said stacker.
 6. A stacker according to claim 5 including deflector means at the input ends of said primary and secondary delivery conveyors for receiving a single stream of blanks and for dividing said single stream into said separate streams.
 7. Apparatus for converting a single stream of reversely orientated blanks into two separate stacks and for delivering said stacks to a delivery unit comprising: primary and secondary delivery conveyors; deflector means at the input ends of said primary and secondary delivery conveyors for receiving said single stream of blanks and for diverting blanks of one orientation onto said primary delivery conveyor and blanks of the other orientation onto said secondary delivery conveyor; lower and upper slow-speed conveyors for receiving streams of shingled blanks from said primary and secondary delivery conveyors, respectively; brake means for periodically interrupting the stream between the primary delivery conveyor and the lower slow-speed conveyor and between the secondary delivery conveyor and the upper slow-speed conveyor to control the number of blanks being processed by said slow-speed conveyors; a first stack-forming magazine at the discharge end of said lower slow-speed conveyor; a second stack-forming magazine at the discharge end of said upper slow-speed conveyor, said second magazine being at a higher elevation than said first magazine; a primary elevator located below said first magazine and having a surface for receiving the stack formed by said first magazine; a secondary elevator located below said second magazine and having a selectively operable laterally movable conveyor surface for receiving the stack formed by said second magazine; said primary and secondary elevators being movable between upper and lower positions with the surface of the primary elevator being above that of the secondary elevator when both elevators are in lower position; a plunger for moving a stack laterally from the surface of the primary elevator to the conveyor surface of the secondary elevator when both elevators are in lower position; and means responsive to movement of a stack from the primary elevator onto the secondary elevator for initiating operation of the conveyor surface of said secondary elevator to move both stacks laterally onto said delivery unit.
 8. ApparatuS according to claim 7 wherein said delivery unit comprises a conveyor.
 9. Apparatus according to claim 8 wherein the conveyor of said delivery unit moves stacks thereon laterally with respect to the paths of stream movement in the apparatus. 